Epiglottitis is primarily caused by which organism?

• A. Staphylococcus aureus
• B. Streptococcus pneumoniae
• C. Pseudomonas aeruginosa
• D. Haemophilus influenzae B

Answer: (D)

Epiglottitis is a dangerous infection that inflames the epiglottis and can block the airway. The classic culprit in children is Haemophilus influenzae type b, because the encapsulated Hib organism was historically the most common cause of pediatric epiglottitis. Vaccination against Hib has dramatically reduced this disease, but the association remains the textbook example of the organism responsible. Hib is a small gram-negative coccobacillus that requires X (hemin) and V (NAD) factors to grow and is best cultured on chocolate agar; its polysaccharide capsule defines the type, with type b being the one targeted by the vaccine. While other bacteria can cause epiglottitis in different settings (including adults), Haemophilus influenzae type b is the organism most classically linked to this condition.